Crystal Sherrison LLC, an investment firm, purchased a 43,000-square-foot office building at 330 Main St. in Hartford from 330 Main Street Associates LP for $2.27 million, or about $52.50 per square foot. The three-story building, which was built in 1986, is in downtown Hartford on the corner of Main Street and Buckingham Street. The property is 68% occupied with the remaining space renting for $16 per square foot. Current tenants include: International Institute of Connecticut and Small Business Administration. Crystal Sherrison LLC will provide maintenance services and property management for the tenants.